Implement ApplyPatchToIndex Class (#50)

* Implement ApplyPatchToIndex Class

Gemfile

@@ -1,12 +1,12 @@
 source 'https://rubygems.org'
 
-gem "mime-types", "~> 2.6.2" 
-gem "rake", "~> 10.4.2"
+gem 'mime-types', '~> 2.6.2'
+gem 'rake', '>= 12.3.3'
 
-gem 'coveralls', require: false
+gem 'coveralls', '~> 0.8.23', require: false
 
 group :test do
-  gem "rspec", "~> 3.4.0"
-  gem "rspec-collection_matchers", "~> 1.1.2"
-  gem "simplecov"
+  gem 'rspec', '~> 3.4.0'
+  gem 'rspec-collection_matchers', '~> 1.1.2'
+  gem 'simplecov'
 end

lib/commit.rb

@@ -100,12 +100,12 @@ def self.new_with_tree(repository, tree, message, actor, parents = nil)
       Commit.new(repository, RevWalk.new(repository).parseCommit(new_commit))
     end
 
-    def self.find_head(repository)
+    def self.find_head(repository, ref = Constants::HEAD)
       repository = RJGit.repository_type(repository)
       return nil if repository.nil?
       begin
         walk = RevWalk.new(repository)
-        objhead = repository.resolve(Constants::HEAD)
+        objhead = repository.resolve(ref)
         return Commit.new(repository, walk.parseCommit(objhead))
       rescue java.lang.NullPointerException => e
         return nil

lib/git.rb

@@ -15,6 +15,8 @@ module RJGit
   import 'org.eclipse.jgit.api.TransportConfigCallback'
   import 'org.eclipse.jgit.transport.JschConfigSessionFactory'
   import 'org.eclipse.jgit.transport.SshTransport'
+
+  class PatchApplyException < StandardError; end
 
   class RubyGit
 
@@ -289,7 +291,11 @@ def checkout(branch_name = "master", options = {})
     end
 
     def apply(input_stream)
-      apply_result = @jgit.apply.set_patch(input_stream).call
+      begin
+        apply_result = @jgit.apply.set_patch(input_stream).call
+      rescue Java::OrgEclipseJgitApiErrors::PatchApplyException
+        raise RJGit::PatchApplyException
+      end
       updated_files = apply_result.get_updated_files
       updated_files_parsed = []
       updated_files.each do |file|